Striation density analysis is often performed on cracked components of devices to ascertain information regarding crack propagation and durability of the components. For example, with respect to gas turbine engines, striation density analysis is often performed on a component of the engine, such as a turbine blade, a turbine disk, or another component, to estimate an amount of operational stress the component has experienced and a number of operational cycles for which the component has operated before the component experienced a crack of a predetermined size. Such estimates can be used to predict the durability of similar components. For example, when a new component is used in an engine, it can then be removed or repaired before it has experienced the amount of operational stress and/or the number of operational cycles experienced by the analyzed component, or, in other words, before it is likely to have a crack of the predetermined size formed therein. In addition, striation density analysis can be used to ascertain similar information about various other devices, systems, and/or components thereof.
Striation density analysis typically involves use of a microscope, such as a scanning electronic microscope (SEM), in calculating a depth of a crack in a component, as well as counting a number of striations (which is often referred to as a striation density) at various locations along the crack. This information is then used, along with a striation density model, to generate a curve, function, and/or other model mapping striation density versus crack depth. This mapping of striation density versus crack depth is then used, along with standard fracture mechanics techniques, to estimate the amount of operational stress the component has experienced and the number of operational cycles for which the component has operated before the crack reached a predetermined size.
While striation density analysis techniques are valuable in ascertaining information regarding components and crack propagation, existing techniques are constrained by limitations in existing striation density models. For example, existing striation density models used to generate the mapping of striation density versus crack depth are not calibrated to specific materials, and therefore may not be of optimal accuracy, particularly during initial stages of crack propagation.
Accordingly, it is desirable to provide a method for generating a calibration for a striation density model with respect to a material of a component. In addition, it is desirable to provide a method for performing striation analysis for a component of an engine using a calibrated striation density model. It is also desirable to provide a program for performing striation analysis for a component of an engine using a calibrated striation density model. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.